Chris, definitely not a super wide. (No noticeable distortion.) Though the three are certainly being hit with a flash pop. (I am guessing a set of Pocket Wizards with a bare bulb or grid spot.) The rest is ambient.
And you're dead-on Jonathan about the hangar. The shadow on the right-hand mains are your giveaway. It's also what gives the people the silhouetted look.
There would be SO many *obvious* ways to shoot SS1. I am glad someone like Wilkes gave us something even better.